Co_(1.5)CrFeNi_(1.5)Mo_(0.5)Ti_(0.5)在不同pH值的3.5%NaCl酸性溶液中的钝化行为研究

Passivation Behavior of Co_(1.5)CrFeNi_(1.5)Mo_(0.5)Ti_(0.5)in 3.5%NaCl Solution with Different pH Values

为了研究Co_(1.5)CrFeNi_(1.5)Mo_(0.5)Ti_(0.5)在不同pH值的3.5%NaCl酸性溶液中的钝化行为,以纯度超过99wt%的钴(Co)、铬(Cr)、钛(Ti)、铁(Fe)和镍(Ni)为原料,用真空感应炉进行熔炼,对熔炼后的Co_(1.5)CrFeNi_(1.5)Mo_(0.5)Ti_(0.5)合金运用X射线衍射仪(XRD)、扫描电镜(SEM)、能谱分析仪(EDS)进行显微组织的表征,采用动电位极化、电化学阻抗谱、恒电位极化、XPS分析等手段来研究其在不同pH值的3.5%NaCl溶液中的钝化行为。结果表明,Co_(1.5)CrFeNi_(1.5)Mo_(0.5)Ti_(0.5)相结构为单一的fcc结构,其微观组织为树枝晶结构;Co_(1.5)CrFeNi_(1.5)Mo_(0.5)Ti_(0.5)合金在不同pH值的3.5%NaCl溶液中具有较强的钝化能力,且随着pH值的增加,其抗腐蚀能力增强;其钝化膜的成分主要包括Cr_(2)O_(3)、Cr(OH)_(3)、Co_(3)O_(4)、MoO_(3)、NiO、Fe_(2)O_(3)、Fe_(3)O_(4)、TiO_(2)。

In order to study the passivation behavior of Co_(1.5)CrFeNi_(1.5)Mo_(0.5)Ti_(0.5)in 3.5%NaCl acid solution with different pH values.Cobalt(Co),chromium(Cr),titanium(Ti),iron(Fe)and nickel(Ni)with a purity of more than 99wt%were melted in a vacuum induction furnace.The microstructure of Co_(1.5)CrFeNi_(1.5)Mo_(0.5)Ti_(0.5)alloy was characterized by X⁃ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS).The passivation behavior of Co_(1.5)CrFeNi_(1.5)Mo_(0.5)Ti_(0.5)alloy in 3.5%NaCl acid solution with different pH values was studied by potentiodynamic polarization,electrochemical impedance spectroscopy,potentiostatic polarization and XPS analysis.The results show that the phase structure of Co_(1.5)CrFeNi_(1.5)Mo_(0.5)Ti_(0.5)is a single fcc structure,and its microstructure is dendrite structure;Co_(1.5)CrFeNi_(1.5)⁃Mo_(0.5)Ti_(0.5)alloy has strong passivation ability in different pH 3.5%NaCl acid solution,and its corrosion resistance is enhanced with the increase of pH value;the composition of passivation film mainly includes Cr_(2)O_(3),Cr(OH)_(3),Co_(3)O_(4),MoO_(3),NiO,Fe_(2)O_(3),Fe_(3)O_(4),TiO_(2).